I9I5-] 



Fauna of the Chilka Lake ; Sponges. 



37 



over leaves that come in contact with them or the shells of mussels attached to the 

 same support, the thin film that they first produce over these bodies, before incor- 

 porating them, is indistinguishable from the less robust phase. The differences 

 between the skeletons of the two phases are no less striking than those between their 

 external forms, and just as in Laxosuberites aquae-dulcioris one phase of the species 

 approaches the genus Prosuberites in certain details of structure (p. 43 postea), so 



O o p n 



o 



Q O ft f? 



O 



o 



î 



Q 



r? 



Fig. 5. — Suberites sericeus, Thiele. 



Spicules of a specimen in phase B, x 255. 



A. — Heads of spicules further enlarged. 



in Suberites sericeus one phase, in this case as in that of the other species the 

 ess robust, approaches the genus Pseudosuberites. 



Before discussing the peculiarities of the two phases in detail it will be as well 

 to say something of the specific characters. 



The most constant of these is the occurrence both of short, relatively stout 

 spicules and of much larger ones in which the shaft is relatively more slender. 



